The trouble is I am not sure they can always be spotted.
I think they can, but they are not always grinding the same axe.
There is a large body of self proclaimed aviation elite in this country, and no doubt elsewhere, who view foreign-paperwork operations with distaste. Fair enough, I can see their point (but don't agree with it). Aviation is not like cars, where driving on a foreign plate gets you off all parking and speeding camera tickets etc - in fact almost everything short of killing somebody - so a limit on residence makes sense.
Only yesterday, one UK former instructor of mine was taking the micky out of my "FAA" CPL/IR. In a friendly way but all too common. I had spent a bigger chunk of my life on getting that piece of paper than on anything else since doing a university engineering degree many years previously, and contrary to popular folklore being on the N-reg does not save any maintenance. The reality is that he himself only had a CPL/IR, until he managed to clock up 1500hrs etc, almost entirely at his students' expense, and he had been in this game for so many years previously he had worked up on the back of so many grandfather routes. In his days, the CPL/IR was a piece of cake (for any aircraft owner who flies a lot) compared to today's, with the self improver routes etc.
But I don't think that most of the top regulators are motivated by this simple prejudice. Most of them are not, and never have been, pilots. A few have or have had a PPL at some stage, so have a notion of what a Cessna looks like. These people are full time committee animals who live for the generation of rules. The concept of eliminating rules is completely off their horizon. Their whole life is about creating new ones. Quite a few, especially in Eurocontrol, are former ATCOs, and I cannot think of a more rule-bound profession. I've met a fair number of Eurocontrol people and most seem to be working in some bunker deep underground.
The EU concept in particular comes with a raft of religious symbology which is a fertile ground for rulemaking. The current EASA position on foreign stuff is "reciprocity". They are happy to sign a treaty (a TREATY - everything in Europe must be a TREATY) with [non-EU] country X for mutual recognition of everything.
If X is some non-entity, they will probably sign happily; their small-town politicians will just love the Brussels treatment - it's a great jolly on expenses.
If however X is the USA, it gets harder because the USA has its own agenda. They only look after some 90% of the world's aviation, directly or indirectly, and it is self evident that their way does work. The USA has also for years had its own treaties and understandings and relationships with many of the individual EU members (including the UK) and doesn't exactly like EASA coming in and saying "WE now represent all these countries". EASA could easily be perceived as the school bully who rules the playground and claims to represent a whole bunch of kids. The EU concept is also a poor fit with the American way of looking at individual rights.
I am sure it will all be resolved in due course, because nobody actually wants to go for the nuclear option, but we are in for a few turbulent years and a great deal of rumour of impending doom.